Device for occult blood testing

ABSTRACT

The device consists of a base sheet of impermeable plastic such as vinyl, or the like, and a guaiac stool receptor sheet adhesively secured thereto. The base sheet is sufficiently larger than the receptor sheet so to form an impermeable skirt which surrounds the receptor sheet so as to form an hermetic barrier protecting the receptor sheet on the underneath one of two of the devices when stacked one on top of the other. A performance/control monitor is included on the device. The monitor includes a peroxidatively active material such as hematin, or the like, which confirms the reactively of the guaiac-impregnated sheet, as well as the activity of the peroxide developing solution. The monitor material is kept out of reactive contact with the guaiac receptor sheet until the developer reagent is applied to the device. A stack of the devices is packed in a sealed container of plastic, or the like, so that the individual devices can be removed from the container one at a time. The devices are designed for use in the physician&#39;s office for reception of stool smears taken manually on a rubber glove or finger cot by the physician from patients.

This invention relates to a device for use in testing stool for occultblood. More particularly, this invention relates to such a device whichis inexpensive to produce, which is designed for use by physicians intheir offices, and which includes a performance/control monitor.

Many devices have been suggested in the prior art for use in obtainingstool samples for analysis for occult blood. Typical of such devices arethose disclosed in U.S. Pat. Nos. 3,996,006 to Pagano; 4,175,923 toFriend; 4,365,970 to Lawrence; 4,259,964 to Levine; and 4,273,741 toLevine.

The above-listed patents all disclose stool sampling devices which aredesigned for use by a patient, generally in the privacy of the home. Atpresent, when stool samples are taken in the physician's office by thedoctor with the use of a rubber glove during a rectal examination, thestool is smeared on a sheet of guaiac-impregnated paper and a developerreagent is applied to the stool smear to ascertain the presence orabsence of occult blood in the stool. The guaiac-impregnated sheetspresently used in the physician's office do not include anyperformance/control monitor which will indicate the reactive state ofthe guaiac when the developer reagent is applied to it. The guaiacreagent used in occult blood testing of stool is susceptible todegradation when exposed to air and/or to light. The guaiac-impregnatedsheets presently used by physicians in their offices are permeable toair and are not packaged to ensure shielding from light or aircirculation. Thus, a stack of such sheets, even when disposed in acarton, is subject to exposure to light and/or air and, thus, prone todegradation of the guaiac during storage of the sheets. It is apparentthat a stool sample analyzed on a sheet of degraded guaiac paper, whichdoes not have a performance/control monitor associated therewith, cangive an invalid reading in that no color change will appear even thoughthe stool has blood in it.

The device of this invention is designed for use in the physician'soffice and serves as a receptor of a stool smear applied to it from thephysician's rubber glove. The sample is taken from the patient by thephysician inserting the finger of a rubber glove clad hand into thepatient's rectum. The testing device includes an impermeable base sheetof pliant plastic material such as vinyl, or the like. Disposed on theimpermeable sheet is an absorbant stool receptor sheet ofguaiac-impregnated paper, or the like. The receptor sheet issufficiently smaller than the base sheet so that a skirt surrounding thereceptor sheet is formed by the margins of the base sheet. This skirt isimpermeable to air and moisture. Disposed on the device, as for exampleon one corner of the receptor sheet, is a performance/control monitorformed from hematin or some other peroxidatively active reagent whichcauses a change in color when the developer reagent is applied to themonitor and the guaiac sheet. The performance/control monitor verifiesthe condition of the guaiac, as well as the developing solution. Themonitor reagent is kept out of reactive relationship with theguaiac-impregnated sheet until the developer reagent is added. Thisprevents formation of a heme-guaiac complex which can form in the priorart devices when the peroxidase positive reagent is applied directly tothe guaiac sheet. Such heme-guaiac complexes as exist in the prior artcan give a false indication of a properly functioning test system, dueto the fact that the heme-guaiac complex is more resistant to light andair degradation than the plain guaiac paper.

The devices may be packaged in stacks of about one hundred, and eachstack is disposed in an air-tight opaque container which is preferablymade from a relatively rigid plastic material, such as polystyrene orABS. Inside the container is a spring loaded follower which pushes thestack toward one end of the container. A slot is formed in the side ofthe container near that one end, the slot providing a port forwithdrawing the devices one at a time from the container. The containercan be secured to a mount which is fastened to a wall in the physician'slaboratory, or, can be provided with suction mounts capable of securingthe container to a lab bench. The end of the container housing thespring is recessed to provide a well for containment of a bottle of thedeveloper reagent. The well also serves as a spring guide for thefollower spring.

It is, therefore, an object of this invention to provide a devicesuitable for use in a physician's office by the physician for analyzingstool samples for the presence or absence of occult blood.

It is a further object of this invention to provide a device of thecharacter described which includes a performance/control monitor toverify the validity of the test results observed.

It is an additional object of this invention to provide a device of thecharacter described wherein the performance/control monitor includes aperoxidatively active reagent which is kept out of reactive contact withthe guaiac-impregnated sheet until the developer reagent is applied tothe device.

It is another object of this invention to provide a device of thecharacter described which is adapted to be packaged in an air-tight, yetloose, stack to protect the guaiac reagent against degradation duringstorage.

It is yet another object of this invention to provide a device of thecharacter described wherein the devices are dispensed from a stackthereof disposed in an opaque container which protects the guaiacreagent from exposure to light.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and advantages of the invention will become morereadily apparent from the following detailed description of preferredembodiments of a device formed in accordance with the invention whentaken in conjunction with the accompanying drawings, in which:

FIG. 1 is an exploded perspective view of a first embodiment of a deviceformed in accordance with this invention;

FIG. 2 is a top plan view of the device of FIG. 1;

FIG. 3 is a fragmented sectional view taken along line 3--3 of FIG. 2;

FIG. 4 is a top plan view similar to FIG. 2 but showing a secondembodiment of the device of this invention;

FIG. 5 is a fragmented sectional view taken along 5--5 of FIG. 4;

FIG. 6 is a side elevational view of a stack of the devices shown inFIG. 2 or 4;

FIG. 7 is a perspective view of a container adapted for holding a stackof the devices of this invention for dispensing individual ones of thedevices from the stack;

FIG. 8 is a sectional view of the container of FIG. 7 showing the mannerin which the devices are held therein;

FIG. 9 is a perspective view similar to FIG. 7 but showing the back ofthe container;

FIG. 10 is a side elevational view of a stack of devices made inaccordance with this invention which are formed as part of a continuousstrip; and

FIG. 11 is a plan view of the strip of FIG. 10.

Referring now to the drawings, there is shown in FIGS. 1 and 2 apreferred embodiment of a stool testing device denoted generally by thenumeral 2, which is formed in accordance with this invention. The device2 includes a basal sheet 4 which is formed from a plastic such as vinyl,or a plastic-paper laminate, or some other pliant material which isimpermeable to moisture and air. A guaiac-impregnated stool receptorsheet 6 is adhesively secured to the basal sheet 4 and aperformance/control monitor 8 is secured to the receptor sheet 6. Thereceptor sheet 6 is preferably a fibrous paper member, and the monitor 8includes a base part 10 made from paper or some similar material, and abutton part 12 which is deposited on the base part 10 and which containsthe absorbed hematin reactant. The base part 10 of the monitor 8 servesto chemically isolate the hematin reactant from the guaiac in thereceptor sheet 6. Thus, the base part 10 of the monitor 8 prevents thehematin reactant from combining with the guaiac to form a heme-guaiaccomplex which, as previously noted, could provide a false indicationthat the guaiac in the receptor sheet is still viable when the developerreagent is applied to the monitor 8. When the developer reagent, such asperoxide, is applied to the button 12, the hematin is eluted from thebutton and the developer and hematin solution spill over the edges ofthe base part 10 onto the guaiac-impregnated receptor sheet 6. If theguaiac is still viable, the characteristic blue color will appear aboutthe base part 10. FIG. 3 illustrates the manner in which the receptorsheet 6 is secured to the basal sheet 4 by adhesive areas A and, also,illustrates the manner in which the reagent button 12 is deposited onthe base 10 of the performance/control monitor 8.

It will be noted from FIG. 2 that the basal sheet 4 extends outwardlybeyond the edges of the receptor sheet 6 sufficiently to form aprotective skirt 5 surrounding the receptor sheet 6. A patientidentification area 7 can be provided on the skirt 5, if so desired.

The device is used as follows. Once the stool sample is obtained by thephysician, a smear is wiped off the rubber glove onto the receptor sheet6 approximately in the center thereof. The developer reagent is thenapplied to the stool smear on the receptor sheet and, also, to theperformance/control monitor 8. If the characteristic blue color isobserved about the stool smear and the monitor, then the presence ofoccult blood in the stool is confirmed. If the blue color appears onlyat the monitor 8, then the absence of occult blood in the stool isconfirmed. If no blue color appears at the monitor location, then thedegradation of the quaiac and/or the developing solution is confirmed,and a second test is made with new reagents.

Referring now to FIGS. 4 and 5, a second embodiment of the device isshown. The second embodiment 3 includes a basal sheet 4 of pliantimpermeable material, having adhered thereto a smaller stool receptorsheet 6. The basal sheet 4 is sufficiently larger than the receptorsheet 6 so as to form an impermeable protective skirt 5 surrounding thereceptor sheet 6. The performance/control monitor 8 is disposed on thebasal sheet 4 beneath a marginal portion of the receptor sheet 6. Thereceptor sheet 6 is secured to the basal sheet 4 by adhesive areas A,and the monitor 8 includes the peroxidatively active reagent button 12which can be deposited directly on the basal sheet 4, or can be on abase member as previously described, which base member is, in turn,secured to the basal sheet 4. The receptor sheet 6 is dry, and thereagent button 12 is also dry prior to application of the stool sampleand developer reagent. Since both of these elements are dry, theperoxidase positive reagent will not be in chemically reactive contactwith the quaiac until the developer solution wets both the receptorsheet 6 and the reagent button 12 and causes all of the chemicals toreactively intermingle. Thus, the device, while including aperformance/control monitor, will not produce a heme-quaiac complexduring storage prior to use.

The device is used in the same manner as previously described with theexception that the developer reagent is applied to the receptor sheet 6over the monitor button 12, whereupon the color change leaches throughthe receptor sheet 6.

Referring now to FIG. 6, a stack of the devices of FIG. 1 or 4 is shown.The stack S is formed so that the devices therein are aligned so as toprovide relatively uniform margins for the stack. Thus, the receptorsheets 6 are disposed generally in vertical alignment, and the skirtportions 5 of the basal sheets 4 overlie each other to form the marginsof the stack S. It will be appreciated that the skirt portions of theindividual devices overlie each other closely so that when two of thedevices are disposed atop each other, the impermeable basal sheetsenvelope the receptor sheet on the lowermost of the two devices toprotect it from air, moisture and light. Thus, in a stack of thedevices, each receptor sheet except the uppermost one is protected so asto guard against degradation of the guaiac. The skirt portions 5 of eachbasal sheet 4 must be extensive enough to thusly protect the receptorsheet 6 on the underlying device.

Referring to FIGS. 10 and 11, an alternative form of the device of thisinvention is shown which is produced in strip form. The strip has acontinuous web W formed from the impermeable plastic material. Thedevices 2 are serially arranged on the strip, with adjacent devices 2being interconnected by flaps 50. Each flap 50 is integral with anassociated one of the devices 2 and has edges 52 which converge toward atear line 54 connecting the flaps 50 with the next adjacent device. Theweb W is folded as shown in FIG. 10 and, thus, packaged in a containeras previously described. To dispense the devices, one pulls the leadflap 50, its attached device 2, and the next flap 50 out of thecontainer. One then ruptures the tear line 54 leaving the trailing flapprojecting from the container for easy grasping when the next device isto be dispensed.

Referring now to FIG. 7, there is shown a preferred embodiment of acontainer from which the devices can be individually dispensed in thephysician's office. The container, denoted generally by the numeral 20,includes a bottom part 22, and a top part 24 which is snap fitted ontothe bottom part 22. The two parts are preferably made from injectionmolded plastic, such as polystyrene or ABS. The container 20 hasapproximately the same cross sectional area as the stack of devicespreviously shown so that the stack retains its configuration when placedin the container. A dispensing slot 26 is formed at a bottom corner ofthe container to allow individual devices to be drawn from the bottom ofthe stack and out of the container. The slot 26 will initially be closedby a strip of impermeable tape, or the like. The top part 24 of thecontainer 20 is formed with a well 28 in its upper surface for thereception and storage of a bottle 30 of the developing reagent.

Referring to FIG. 8, the interior of the container 20 is shown. Thestack S of devices is biased downwardly in the container 20 by afollower 32 which, in turn, is biased by a follower spring 34. Thespring 34 is a coil spring which ensleeves the well 28 so that the wallof the well 28 serves as a spring guide for the follower spring 34. Thefollower 32 will preferably be formed from an impermeable material so asto protect the receptor sheet on the topmost device in the stack S. Itwill be noted that the developer reagent bottle 30 preferably fitscompletely within the well 28 so that the entire package can beshrink-wrapped for shipment to physicians' offices. The bottom of thecontainer 20 may be provided with profiled projections 36 integral withthe remainder of the container which are adapted to have rubber suctioncups 38 (shown in phantom) secured thereto. The suction cups 38 adaptthe container for securement to the top of a lab bench, or the like.

Alternatively, the back wall of the container 20 may be formed with anintegral rib 40 which is profiled so as to be removably slidablyinsertable into a mating slot formed in a mounting piece which can befastened to a wall in the physician's office.

It will be readily appreciated that the device of this invention isinexpensive to produce and yet dependable in operation. The provision ofa performance/control monitor on the device which is not in a chemicallyreactive relationship with the receptor sheet until the developerreagent is added to the device ensures proper operation of the monitor.The developer reagent wets the peroxidatively active monitor reagent andthe guaiac and allows both to combine in the chemical reaction whichresults in the characteristic color change when the guaiac has notdegraded during storage. The devices are formed so that the guaiacimpregnated receptor sheets will be protected against air, moisture, andlight when the devices are disposed in a stack. The stacks are packagedin opaque containers which have means for spring loading the stack sothat individual ones of the devices can be drawn from the container fromthe bottom of the stack. The container has a well in its top wall whichserves as a spring guide for the spring loading means and also houses abottle of developer reactant used in the testing.

Since many changes and variations of the disclosed embodiments of theinvention may be made without departing from the inventive concept, itis not intended to limit the invention otherwise than as required by theappended claims.

What is claimed is:
 1. A device for testing stool samples for occultblood, said device comprising:(a) a stool receptor sheet, said receptorsheet being impregnated with guaiac; (b) a performance/control monitoron said device, said monitor including a dry button of a water-solublehematin material positioned so as to be operable, when wetted with adeveloper reagent, to react with the guaiac in said receptor sheet toindicate the activity level of the guaiac and the developer reagent; and(c) means preventing said hematin material from reacting with the guaiacin said receptor sheet prior to being wetted with the developer reagent.2. The device of claim 1 further comprising an impermeable pliant basalsheet on which said receptor sheet is mounted.
 3. The device of claim 2wherein said basal sheet is sufficiently larger than said receptor sheetto form an impermeable skirt surrounding said receptor sheet operable toprotect a receptor sheet on another of the devices stacked below thebasal sheet from air and moisture.
 4. The device of claim 2 wherein saidmonitor includes a paper base member mounted on said receptor sheet, andsaid button is mounted on the surface of said base member distal of saidreceptor sheet wherein said base member forms said means preventing saidhematin material from reacting with the guaiac.
 5. A device for testingstool samples for occult blood, said device comprising:(a) a stoolreceptor sheet, said receptor sheet being impregnated with guaiac; (b) adry button of a water-soluble hematin material operable, when wettedwith a developer reagent, to react with the guaiac in said receptorsheet to provide an indication of the activity level of the guaiac andthe developer reagent; and (c) a base member sandwiched between saidbutton and said receptor sheet and secured to each, said base memberpreventing said hematin material from reacting with the guaiac in saidreceptor sheet prior to being wetted with the developer reagent.
 6. Thedevice of claim 5 wherein said base member is made of paper.
 7. A devicefor testing stool samples for occult blood, said device comprising:(a)an air impermeable pliant basal sheet; (b) a stool receptor sheetmounted on said basal sheet and at least partly spaced therefrom, saidstool receptor sheet being impregnated with guaiac; and (c) a dry buttonof a water-soluble hematin material disposed in said space between saidbasal sheet and said receptor sheet and secured to said basal sheet indry form prior to mounting said receptor sheet on said basal sheet andin a manner such that said hematin material is not in chemicallyreactive contact with the guaiac in said receptor sheet until adeveloper reagent wets both the receptor sheet and the dry button, saidmaterial being operable, when wetted with the developer reagent, toreact with the guaiac in said receptor sheet to provide an indication ofthe activity level of the guaiac and the developer reagent.